Polymerization of cycle oil from high-temperature steam cracking process



Patented Mar. 14, 1950 POLYMERIZA'I'ION CYCLE OIL FROM HlGH -TEMPERATURESTEAM CRACKING PROCESS Minor 0. K. Jones',v Mountainside, N. J.,assignor to Standard Oil Development Company, a. corporation: of,Delaware No Drawing. Application November 30, 1945, Serial No. 632,105

fi Claims 1:

This invention relates to a process. for refining a highly cracked gasoil to obtain a satisfactory heating oil and valuable resin by-products.

Especially since there has been a great demand for normally gaseousunsaturated hydrocarbons, such as ethylene and butadienes, intensivecracking processes have been developed for converting large proportionsof petroleum feed stocksto. these gases. These cracking processes yieldnaphtha distillates that contain considerable amounts of aromatics mixedwith unstable unsaturated hydrocarbons. They also yield a heavy tar anda cycle gas oil or intermediate distillate fraction which containsconsiderable amounts of arcmatic compounds and unstable hydrocarbons.

The complexity and instability of the cycle gas oils formed by intensecracking make them difficult to use in the same manner as. ordinarycycle stocks. Only a small portion of highly unstable cycle gas oils canbe recycled satisfactorily for intense recracking; frequently none isrecycled. Therefore, large quantities of the highly cracked gas oilshave to be withdrawn from the cracking system. They are unsatisfactoryfor use as. a domestic heating oil even after being given a customaryacid treatment and after blending with a large proportion of a regularrefined domestic heating oil. They also are highly odoriferous.Therefore, there has been an urgent requirement for a method of treatingsuch highly cracked gas oils to recover commercially-useful productstherefrom.

An object of this invention is to provide a method of treatingeconomically thedescribed gas oils of high instability to produce morevaluable commercial products therefrom.

Another object is to provide a method of: treating the highly crackedintermediate fraction to yield satisfactory heating oils andcommercially useful thermoplastic resins so that the fraction is madeentirely utilizable in commercial products.

High temperature cracking yields aromatic gas,- oline distillates whichhave been found difficult to treat with active clays, but the controlledcatalytic process of the present invention is. surprisingly effectivefor treatment of higher boiling cycle oil distillates formed by crackingat high temperatures in the range 1050 F. to 1500 F. in the presence ofsteam at low pressures of about 1 to 2 or several atmospheres. Thesecycle distillates boiling in the range of about 350 F. to 700 F.,relatively high in unstable, unsaturated compounds and high boilingphenols, are exceptionally adapted for a catalytic clay treatment toform the desired by-products.

A procedure for attaining the stated objects consists in treating acycle gas oil from a hightemperature steam-cracking of gas oil feed witha catalytically active clay at a temperature in the range 350 F. to 450F., under a pressure of about 15 to 400 pounds per square inch absolute,and at contact rate from /2 to 2 Vol. oil/vol. clay/ht.

The. oil is preferably percolated through a fixed bed of catalyticallyactive, clay with adjusted temperature, pressure, and contact time, and;the liquid product separated from the clay is rerun to recover adistillate. and polymer as bottoms, preferably after Washing withcaustic. The oil filters down. through the clay, which is in granular orlump form, and washes away polymer from the clay. The clay is of anadsorptive type which is catalytically active for promoting polymerization of unsaturated hydrocarbons. For example, floridiinv earth,fullers earth, acidtreated clays, heat-activated clays, or similarlyactive siliceous, adsorbents, such as zeolites, may be used,

For the purpose of illustration, a preferred mode of operation will bedescribed with reference to atypical cycle gas oil from ahigh-temperature steam-cracking process in the following example.

TABLE I Cracking operation data Fresh feed to cracking furnace, v

lbs/hr. 40,322 Total feed. to cracking. furnace,

lbs/hr; 41,517 Steam feed to: cracking. furnace.

lbsz/hr. 8,025 Cracking temperature, coil outlet,

F. 1 2124246 Cracking pressure, pounds/square inch: 25

Products:

Tar, lbs/hr. 7,110 Tar gravity; A. P. I. 8.2 Cycle gas oil, lbs/hr 5,870Cycle gas oi-lgravity, A. P. I. 24.2 Aromatic naphtha distillate lbs/hr.9-,980 Distillate gravity, A. P. I 49.4

The clay-treating run was made at 392? F. average clay temperature,pounds per square inch gauge. pressure, and 1 volume of oil. per volumeof active clay per hour feed rate...

The clay-treated oil product was caustic 3 Washed and rerun to separate8l% heating oil distillate as overhead from 16% polymer bottoms.Inspections of the heating oil cut in comparison with inspections of thecycle gas oil stock subjected to the clay treating are given in thefollowing Table II.

TABLE 11 Clay treatment Feed Product Heating Oil Inspections:

Gravity, A. P. I 23. 4 27. 5

Aniline Point, F 56 88 Diesel Index 13. l 24. 2

Acid Heat-ASTM, "F 104 48 Phenol Number, rug/100 ml. equiv. t-amylphenol 7, 500 250 Bromine Number, cg./g 9. 2 21.2

Diene Number, cg./g 5. 1 1. 2

Storage Test, g. se

months) 36 11 Distillation:

I. B. "F 352 250 F. B. P 636 606 Recovery, 97. 5 98. 5 Burning Quality lUnsatisfactory. 2 Satisfactory.

The resulting heating oil product of the catalytic clay treatment wassuitable in all characteristics for domestic heating oil requirementsexcept in forming slightly more sediment on storage than is formed bythe best regular heating oils. Such a product can b blended in largeproportions with lower sediment forming oils to give a highlysatisfactory heating oil, or can be made entirely satisfactory by makingthe clay treatment conditions a little more effective in removingsediment-forming components, as by prolonging the contact time orslightly increasing the temperature in the optimum range to about 400 F.or slightly above, yet below 450 F. When the storage test shows aSlightly lower sediment content in a six-month storage test, the oil iscompletely satisfactory even without blendmg.

The polymer resin recovered as bottoms from the rerunning of theclay-treated-oil had the following characteristics:

Gravity 4.9 Flash, F 390 Via/210 F., S. S. U 293 Diene number, cg./g 4.6

The resin is solid at room temperature and is tacky when heated. It hassatisfactory appearan adhesive for wood veneer, adhesive for sawdust incompounding wallboard, extender and plasticizer for coatingcompositions, plastics, natural and synthetic rubber compositions, andthe like. It can be sulfurized or be co-vulcanized with rubber orunsaturated copolymers.

The steam-cracked cycle oils are indicated, by the phenol number, tohave a rather high phenolic content, of the order of 5% to 10%, and areindicated, by the diene number, to have a rather high content ofconjugated double bond compounds. Evidently, from the results obtained,the phenolic and conjugated double bond compounds enter, to a largedegree, into th formation of the resin with unstable sediment-formingcomponents when the oils are given the described treatment and thesecomponents are removed from the desired heating oil components. Thechemical composition of the recovered resins is, therefore, complex andunique.

The conditions of the treatment for obtaining satisfactory heating oiland resin products from the cycle stocks boiling in the range 350 F. to700 F. have to be carefully controlled, because with excessive heating,the active adsorbent is capable of accelerating decomposition reactionswhich result in degradations of the products. The optimum temperatureis, therefore, established to be of the order of 350 F. to 450 F. Thetreating pressure is variable but should be sufficient to maintain theoil in liquid phase, and accordingly is generally increased withincrease in the treating temperature. However, the space velocity shouldbe kept within prescribed limits like the temperature in order to obtainadequate treatment without undesired decomposition.

The invention is not intended to be limited by the specific example,which has been given to illustrate how a. preferred embodiment isaccomplished. Various changes may be made and are intended to comewithin the scope of the invention defined in the appended claims.

I claim:

1. The method of obtaining more valuable products from ahigh-temperature steam cracked cycle oil boiling in the range of about350 F. to 700 F., which comprises contacting said oil in liquid phasewith an active polymerizing adsorbent at a space velocity between to 2volumes of the oil per volume of the adsorbent per hour while theadsorbent is at a temperature in the range 350 F. to 450 F.

2. The method of producing stable heating oil and useful polymerby-products from a high-temperature cracking process, which comprises incombination the steps of cracking a gas oil feed at 1050 F. to 1500 F.in the presence of steam at about 1 to several atmospheres of pressure,separating from resulting cracked products an intermediate fractionboiling in the range 350 F. to 700 F., percolating said fraction inliquid phase through a catalytic adsorptive clay at a space a velocityof to 2 volumes of the fraction per volume of the clay per hour whilethe clay is at temperatures in the range 350 F. to 450 F., causticwashing the thus clay-treated fraction, distilling from the washedclay-treated fraction a heating oil and recovering a polymer bottomstherefrom.

3. The method of producing stabl heating oil and useful polymerby-products, which comprises the steps of cracking a gas oil feed atabout 1200 F. in the presence of steam, separating from resultingcracked products a cycle oil boiling in the range 350 F. to 700 F.,contacting said cycle oil with adsorptive clay for a reaction period ofabout one hour while the clay is at an average temperature of about l00F. and between the limits of 350 F. and 450 F., caustic washing the thusclay-treated oil, distilling about 84% of the washed, clay-treated oiloverhead to recover a stable heating oil distillate, and recoveringabout 16% of the washed clay-treated oil as polymer bottoms.

4. The method of obtaining more valuable products from ahigh-temperature steam-cracked petroleum oil fraction containingsubstantial amounts of phenolic and conjugated double bond componentsboiling in the range of 350 F. to 700 F., which comprises contactingsaid oil fraction in liquid phase With a catalytically active siliceousadsorbent at a space velocity of to 2 volumes of the oil per volume ofthe adsorbent per hour while the adsorbent is at a temperature in therange 350 F. to 450 F., and separating from the thus-treated oilfraction a heating oil product of relatively low phenolic, conjugateddouble bond and sediment-forming compound content.

5. A process of preparing a stabilized heating oil and a useful resinfrom a cycle gas oil of high-temperature steam cracking boiling in therange of about 350 F. to 700 R, which comprises polymerizingsediment-forming components, phenolic components, and diene componentsof said cycle gas oil to a polymer resin as said oil is contacted inliquid phase with a polymerizing adsorbent at a temperature in the rangeof 350 F. to 450 F. with a space velocity of to 2 volumes of said oilper volume of the adsorbent per hour, washing away said resin from theadsorbent by unreacted components of the thus treated oil, andseparating said unreacted components from the resin by distillation toob- REFERENCES CITED The following references are of record in the fileof this patent:

UNITED STATES PATENTS Number Name Date 1,337,523 Leslie Apr. 20, 19201,766,927 Morrell June 24, 1930 1,919,723 Hyman July 25, 1933 2,090,333Osterstrom Aug. 17, 1937 OTHER REFERENCES Sachanen: Conversion ofPetroleum, pages 374-379, Reinhold, New York (1940)

1. THE METHOD OF OBTAINING MORE VALUABLE PRODUCTS FROM AHIGH-TEMPERATURE STEAM CRACKED CYCLE OIL BOILING IN THE RANGE OF ABOUT350*F. TO 700*F., WHICH COMPRISES CONTACTING SAID OIL IN LIQUID PHASEWITH AN ACTIVE POLYMERIZING ADSORBENT AT A SPACE VELOCITY BETWEEN 1/2 TO2 VOLUMES OF THE OIL PER VOLUME OF THE ADSORBENT PER HOUR WHILE THEADSORBENT IS AT A TEMPERATURE IN THE RANGE 350*F. TO 450*F.